The present invention relates in general to the field of combustion engine cooling.
More specifically, the invention relates to a unit for cooling an internal combustion engine, the unit comprising:                a crankcase exchanger designed to allow the circulation of a heat transfer fluid for cooling a crankcase;        a main radiator;        an additional radiator;        a cooling circuit designed to carry the heat-transfer fluid between the crankcase exchanger and the radiators.        
To cool engines use is made of an exchanger intended to collect heat energy from a region of the engine that is to be cooled and this heat energy is carried to one or more radiators.
This is why numerous combustion engine manufacturers have developed various solutions aimed at cooling engines.
An engine cooling unit of the type defined hereinabove is described, for example, in French patent document FR2884865 which discloses a unit provided with a main radiator and with an additional radiator too enabling the cooling capacity of the main radiator to be increased when the additional radiator is in operation.